1. Technical Field
The present invention relates to a seat belt retractor for a vehicle. More particularly, the present invention relates to a seat belt retractor having a cinch mechanism for blocking seat belt withdrawal from the retractor.
2. Description of the Prior Art
U.S. Pat. No. 4,597,546 discloses a seat belt retractor having a cinch mechanism for blocking seat belt withdrawal from the retractor. The cinch mechanism includes a lever which engages a portion of the seat belt wound on a spool of the retractor. As the seat belt is unwound from the spool, the lever moves. When the lever reaches a predetermined position, a locking pawl is moved into engagement with a ratchet wheel fixed to the spool to prevent further withdrawal of the seat belt. An overcenter spring acts between the frame of the retractor and the locking pawl The overcenter spring moves the locking pawl into engagement with the ratchet wheel and holds the locking pawl in engagement with the ratchet wheel. Other known seat belt retractors having cinch mechanisms with overcenter springs are disclosed in U.S. Pat. Nos. 4,427,164; 4,729,524; and 4,765,558.